Emulsifiable oil composition



United States Patent EMULSIFIABLE OIL COMPOSITION John D. Oathout, Cranford, N. J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application June 18, 1954, Serial No. 437,875

17 Claims. (Cl. 25 233.3)

The present invention relates to an emulsifiable oil composition and particularly to a so-called soluble cutting oil such as is used in metal working operations.

This application is a continuation-in-part of application Serial No. 291,977, filed June 5, 1952, and now abandoned.

In the prior art the advantages of the so-called soluble or ernulsifiable cutting oils have been widely recognized. Sincethese oils are emulsifiable with water they can be combined with various proportions of water to simultaneously lubricate and cool the tools and the metal parts which are being operated upon. The prior art has c'onsidered it essential to use certain types of emulsifyiag ingredients in relatively large proportions in order to secure good solubility or emulsifiability in various proportions of water. In general, it is desired that soluble cutting oils be compatible with roportions of l to 50 or more parts of water for each part of the oil composition. Hence, it is essential that the emulsifying agents be highly elfective.

and neutralizing with sodium hydroxide or the like have been Widely used in soluble oil's. These oil soluble sodium petroleum sulfonates are in general demand for various purposes including detergents, lubricating oil additives and the like. They are relatively expensive and often in short supply. Commercial cutting oils commonly employ as much as to by weight, on a dry basis, of these sul fonate's, proportions of 12-15% being particularly common. Hence, compositions of this type consume large quantities of the relatively .se'a-rce and expensive sulfonates. One object of the present invention is to replace these sulfonates with other much less expensive ingredients which give comparable or even superior results.

In a copending application, Serial No. 291,978, and now abandoned, filed contemporaneously with Serial No. 291,977, there is disclosed an improved soluble oil composition of a related type. Therein certain naphthenic acid soaps and other ingredients are derived from pipe still bottoms, i. e. residues from acid-treated and caustic-treated distillation operations are combined with .sulfonates or rosin soaps, etc. to make a relatively in expensive product of excellent emulsion characteristics.

In the present case, another inexpensive residue rnaterial from a different type of refining operation is utilized as an important ingredient. In the extraction of undesired naphthenic acids and related materials from lubricating oil, especially Colombian or Coastal stocks of high naphthenic content, one process involves the use of aqueous solutions of an aromatic sulfonate material rich in sodium xylene and/or toluene sulfonates, etc. and sodium hydroxide, which is called Nap'ex solution. The aromatic sulfonate material used in this solution is ".ice

' obtained as the neutralized sulfuric acid extract from More specifically, the lubricating oil distillates are treated with about l5-25 lbs. of strong sulfuric acid of about 98% strength per barrel of oil. A sludge is formed which is allowed to separate. The acid oil layer is subsequently extracted with about 4-10 bbl. peflOQ bbl. of oil, of a Napex solution of the type described above, e. g. a solution containing about 26% of sodium toluene and xylene sulfonates, about 12.5% of inorganic salts, about 3.5% of free sodium hydroxide and about 58% of water. The oil-Napex mixture is preferably heated to about -2l0 F., for example by steam blowing, and allowed to settle, at which point the spent Napex solution containing dissolved naphthenates and sulfonates and some oil separates as the bottom layer or extract and is drawn off. The Napex solution may be recirculated one or more times but eventually it becomes loaded with sludge or otherwise spent. The spent Napex solution is then cooled, treated with 1-2 volumes of water and allowed to settle. An organic upper layer is separated. Alternately, the water contained in the spent Napex solution may be removed therefrom by flashing or distilling and any solid inorganic material remaining in the organic material may be removed by decanting or filtering.

The organic material so separated, which normally contains about 3-20 wt. percent of water-soluble low molecular weight sulfo-nates, may be used for the purposes of the present invention. If it is desired further to purify this material, it may be acidified to a pH of 3 and then treated with aqueous sodium hydroxide while removing water which separates upon acidification and alkalinization. Such purification treatment may reduce the low molecular weight sulfonate content of the Napex solution to less than 3 wt. percent. The sodium soap concentrate thus formed is blown with hot air until the concentrate is substantially free of water.

The Napex solution so obtained is a relatively heavy sludge which contains relatively large proportions of soaps, including substantial proportions of naphthenates and some sulfonates. These sludge or spent materials are used as emulsifying agents in soluble oils. They may be used also in combination with conventional (and relatively expensive.) sulfonates such as oil-soluble petroleum sulfonates, or they may, according to one aspect of the invention, be used with other soaps, such as the alkali metal rosin soaps, e. g. the potassium or sodium rosinates sold commercially by Hercules Powder Company under the trade names Dresinate 92, Dresinate' 93," etc. Alternatively the sulfonates, rosinates, and other soap and non soap emulsifiers, including the partial esters of polycarboxylic acids and other hon-ionic emulsifiers may be used with the spent Napex type solutions in various combinations.

The invention, therefore, has the advantage of replacing a relatively expensive ingredient (sodium or other oilsoluble high molecular weight sulfonate.) hitherto deemed essential with amaterial containing substantial proportions of water-soluble aromatic low molecular weight sulfonates, which has previously been considered largely a waste, with eminently satisfactory results. In some cases Patented Aug. 13, 1957 it may be desirable to retain some of the relatively expensive sulfonate, especially where rust prevention in machined steels and other ferrous metals is of paramount importance. Hence, proportions of 2-25 by weight of the spent Napex type product may be used in mineral base oil of lubricating grade, along with 110% of other soap-type emulsifying agents. The Napex product will have a soap content, primarily sodium naphthenate and high and low molecular weight sulfonates, of 2575% by weight. In general, the naphthenate soap content is between 10'and 50% of the spent Napex" product, so that an oil containing 2-25% of the spent Napex will contain about 02-12 or 13% of sodium naphthenates. Rosin soaps, where used, may be present in approximately equal proportions, i. e. l or by weight of the soluble oil composition. The total sulfonates present inthe spent Napex may comprise about 5-5 0% of the spent .Napex or about 01-15% of the oil product; In typical cases which will be illustrated below, the high-molecular weight, oil-soluble sulfonates (about 350-500 mol. wt.) made up about Ms-Vz of the soap content of the spent Napex. The content of low molecular weight water-soluble sulfonates may be about 0.5-20% by weight of the spent Napex. Normally the weight ratio of naphthenates to high molecular weight sulfonates is about 0.5-5 :1. In all cases, however, requirements for the usual expensive oil-soluble petroleum sulfonate ingredients are materially reduced and good use is made of a product formerly considered quite worthless. As in said copending application, a balancing agent may be needed.

The invention will be more fully understood by reference to specific examples:

Example I Four samples of spent Napex product, considered representative of normal production at a large refinery, were taken. Two of these samples (a) and (a') were taken from the refining of a Coastal oil of about 1,000 S. S. U. viscosity at 100 F., and two samples (1)) and (b') from the refining of another Coastal oil of about 100 S. S. U. at 210 F.

Samples (a) and (b) were spent Napex product obtained as follows. The Coastal distillates were treated with approximately 20 lbs./bbl. of 98% black sulfuric acid. Atter removal of sludge the acid oil was extracted with about 6 bbls. of the fresh Napex solution, specifically described above, per 100 bbls. of oil. The oil- Napex mixture was heated to 190 F. by blowing with steam. The spent Napex solution was then allowed to separate as the bottom layer. On cooling to about 90 F. a water layer separated, which was discarded. The organic layer was blown with air to remove water. About 12 bbls. of spent Napex product were recovered per 100 bbls. of oil treated.

Samples (a) and (b) were spent Napex products obtained as described above which were, prior to air blowing, further acidified with sulfuric acid to a pH of 3 followed by alkalizing with sodium hydroxide to a pH of 10.

These four samples had the following composition:

Percent Oil 47. 0 72. 0 65.2 42. 0 Percent Inorganic Salt 3. 7 0. 2 5. 3 1. 7 Percent Total S0ap 48. l 28. 0 29. 5 48. 0 Combining Wt. 01' Soap (as Na) 422.0 405. 0 Percent N aphthenate 22. 19. 6 10. 5 l5. 8 Combining Wt. of Naphthenate (as N a) 495. 0 450. 0 540. 0 545. 0 Percent High Molecular Weight Sulfonate 22. 8 4. 7 l5. 6 16. 3 Combinin Wt. of High Molecular Weight Sulfonate (as Na) 417. 0 393. 0 400. 0 447. 0 Percent Low Molecular Weight Sulfonate 0. 7 3. 4 2. 0 17. 2 Combining Wt. of Low Molecular Wt. Sulionate (as Na) 231. 0 103. 0 200.0 135.0

4': Three blends of products (a) and (b) were prepared. The following were prepared from product (a):

Blend No I III Composition, Wt. Percent:

a Mineral Lube Oil, 45 S.S.U.

On the basis of emulsibility and blend appearance,

blend II was selected as the best of these three.

' A similar study of Napex sample (b), blended at concentrations which resulted in the same soap concentrations as reported above (5, 7.5, and 10%) gave similar results: the 5% (soap basis) blend could not be brought into balance, and was rejected. The 7.5% soap blend was best, showing fair-good emulsibility, no blend separation, and a 40/ lemulsion resulted in a rust rating of 0. Emulsion stability was rather poor showing a separation of 25 cc. of cream after 24 hours. This probably may be corrected by more careful balancing with triethanolamine and coupling agents. The blend containing 10% Napex soap required 34% Napex concentrate in its blend, with the result that the blend was too viscous to be satisfactory.

Incorporation of 4.0 wt. percent Dresinate 93, a liquid potassium rosinate (containing 12.5% diethylene glycol) manufactured by the Hercules Power Company, in the blends containing 5% Napex soaps resulted in marked improvement in these blends with respect to emulsibility andemulsion stability. Rust ratings were somewhat inferior, however.

On the basis of the data obtained in the screening tests, larger soluble oil samples were prepared, and studied more fully. laboratory results are as follows:

Blend No VI Nape er Mineral oil of 45 SSU osity Triethanolamine Emulsibility 1.6 Good-Ex cellent.

1 This blend appeared cloudy at all times and could not be balanced satisfactorily. Rejected.

2 Weeks at Room Temperature 1 Week at 35 F Rust Rating:

40/1 Emulsion Staining No Separation No Separation 2-3. 2 2,2. Moderate Stain 1n Emulsion La er CSC, 1 10/1 Emulsion: 3 hrs. at 122 Fa ll'3 2 h 3 -3 1 Copper Strip Corrosion. 3 Sea e: J-l to J-10; J 3 denotes very light stain.

The compositions of these blends, and

Additional blends were prepared from Na gaeirh-solution (11') and tested as indicated in the table below.

It will be noted that these blends which contained about equal proportions of oil-soluble high molecular weight sulfonates and water-soluble low molecular sulfonates and about equal proportions of naphthenates and high molecular weight oil-soluble sulfonates had commercially acceptable emulsification characteristics. This result was obtained without further balancing the blends in the manner described above. The emulsibility and emulsion separation of these blends may be easily changed from a rating of Fair and Good, respectively, to a rating of Good-Excellent and equivalent ratings, by balancing the blends as indicated above.

From these data, it appears that blends incorporating Napex concentrates with or without Dresinates compare favorably in properties with competitive brands of soluble oils. The Napex soluble oils appear to be superior to some formulations with respect to emulsibility (ease of emulsion formation) and blend stability.

Blends of the type described above not only have good emulsification properties in various proportions of water but they also have good load carrying properties.

The triethanolamine used in the blends mentioned above was employed as a balancing agent. In some cases, it might be necessary to use an acid, e. g. oleic or related fatty acid instead of the amine, to bring the pH value to the desired level or about 7.2 to 8.5, as explained more fully in the copending application filed simultaneously with Serial No. 291,977 and mentioned above (Serial No. 291,978).

Also, as mentioned in said copending application, it is desirable to use as a coupling or blending agent an aliphatic alcohol, preferably diethylene glycol, in proportions up to preferably about 1% to 4%, based on the weight of the oil blend. Other alcohols, such as isopropyl, may be used but diethylene glycol is somewhat superior to facilitate blending the oil with water.

The present invention contemplates also the preparation of a blending or emulsifiyng agent per se. In such cases, 4075% of the spent Napex solution may be combined with 25-55% of another soap of good emulsifying properties, e. g. rosin soap. It is preferred to use at least 20% of rosin soap where the sulfonate content of the spent Napex solution is low but it may be omitted altogether where the sulfonate content of the Napex approaches half of its total soap content. Even in such cases it may be desirable to use up to 3% of such soap, as in blend VI, above.

Diethylene glycol or other assisting agents may be used in proportions up to or more and when needed, an alkanolamine or a fatty acid is employed to bring the pH value to the desired level as previously explained. A small amount of water added to the oil, e. g. (up to 3% or so) aids in emulsification.

It will be understood that conventional modifiers may be used also, such as rust inhibitors (e. g. phosphites, chromites, etc.), extreme pressure agents, oiliness agents, etc., as will be obvious to those skilled in the art. In some cases synthetic lubricating oils, e. g. diesters, com plex esters, etc. of appropriate viscosity, as well as synthetic hydrocarbon oils may be used as a part or all of the oil base. The viscosity of the oil may vary over a wide range, e. g. from 35-1000 S. S. U. at 210 F., the lower part of this range, up to S. S. U. or so, usually being more desirable.

What is claimed is:

1. An emulsifiable metal working oil composition comprising a major proportion of a lubricating oil and a minor proportion suificient to render said oil emulsifiable, of a sulfonate-naphthenate material obtained by separating an organic layer from the extract formed in the extraction of mineral base lubricating oil of high naphthenic content with an aqueous solution of water-soluble sulfonate material selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof, and sodium hydroxide.

2. A composition as claimed in claim 1 in which said naphthenic lubricating oil is an oil treated with strong sulfuric acid prior to said extraction.

3. A composition as claimed in claim 1 which contains about 225 wt. percent of said material.

4. A composition as claimed in claim 1 in which said material contains a total of about 25-75 wt. percent of sodium sulfonates andna'phthenates, based on said niaterial.

5. A composition as claimed in claim 1 in which said material contains about 10-50 wt. percent of sodium naphthenates, based on said material.

6. A composition as claimed in claim 1 in which said material contains about 05-20 wt. percent of low molecular weight water-soluble sulfonates selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof, based on said material.

7. A composition as claimed in claim 1 in which the weight ratio of naphthenates to high molecular weight oil-soluble sulfonates in said material is about 0.5-5 :1.

8. A composition as claimed in claim 1 in which said material contains about 0.1-15 wt. percent of total sulfonates, based on said composition.

9. A composition as claimed in claim 1 in which about As-V2 of the total naphthenate and sulfonate content of said material is high molecular weight oil-soluble sulfonate.

10. A composition as claimed in claim 1 which contains about 1-10% by weight of rosin soap, based on said composition.

11. A composition as claimed in claim 1 which contains about 1-4 wt. percent of a coupling agent selected from the group consisting of glycols, aliphatic alcohols and water.

12. An emulsifying agent for lubricating oils comprising about 25 to 55% by wt. of a soap having emulsifying properties and about 40-75% by weight of a sulfonatenaphthenate material obstained by separating an organic layer from the extract formed in the extraction of mineral base lubricating oil of high naphthenic content with an aqueous solution of water-soluble sulfonate material selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof, and sodium hydroxide.

13. An oil composition of the approximate formula by weight:

74-85% mineral base lubricating oil 10-21% of a sulfonate-naphthenate material obtained by separating an organic material from the extract formed in the extraction of mineral base lubricating oil of high naphthenic content with an aqueous solution of water-soluble sulfonate material selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof, and sodium hydroxide, said material containing about 05-20 wt. percent of low molecular weight water-soluble sulfonates based on said material and naphthenates and '7 6 high molecular weight oil-soluble sulfonates in a weight I ratio of about 0.5-5 :1 3-4% diethylene glycol 0.52% water 0.5-1.5 triethanolamine 14. A composition as claimed in claim 13 which contains about 1-10% of alkali metal soap or" rosin acids.

15. An oil composition of the approximate formula by weight:

75-84% mineral lubricating oil 10-20% of a sulfonate-naphthenate material obtained by separating an organic material from the extract formed in the extraction of mineral base lubricating oil of high naphthenic content with an aqueous solution of water soluble sulfonate material selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof and sodium hydroxide, said material containing about 0.520 wt. percent of low molecular Weight water-soluble sulfonates, based on said material and naphthenates and high molecular weight oil-soluble sulfonates in a weight ratio of about 3-6% 'of alkali metal soap of rosin acids 17. An emulsifiable metal working oil compositioncomprising a major proportion of a lubricating oil and a minor proportion suflicient to render said oil emulsifiable, of a sulfonate-naphthenate material obtained by adding water to the extract formed in the extraction of a mineral base lubricating oil of high naphthenic content with an aqueous solution of a water-soluble sulfonate material selected from the group consisting of sodium xylene sulfonate, sodium toluene sulfonate and mixtures thereof, and sodium hydroxide, and recovering said sulfonatenaphthenate material as an organic layer of said waterdiluted extract.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN EMULSIFIABLE METAL WORKING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL AND A MINOR PROPORTING SUFFICIENT TO RENDER SAID OIL EMULSIFIABLE, OF A SULFONATE-NAPHTENATE METERIAL OBTAINED BY SEPARATING AN ORGANIC LAYER FROM THE EXTRACT FORMED IN THE EXTRACTION OF MINERAL BASE LUBRICATING OIL OF HIGH NAPHTHENIC CONTENT WITH AN AQUEOUS SOLUTION OF WATER-SOLUBLE SUFONATE MATERIAL SELECTED FROM THE GROUP CONSISTING OF SODIUM XYLENE SULFONATE, SODIUM TOLUENE SULFONATE AND MIXTURES THEREOF, AND SODIUM HYDROXIDE. 